1. Field of the Invention
This invention relates to improvements in micro-machining, perhaps in a particular example to improvements in manufacturing motion sensors.
2. Discussion of Prior Art
It is known to produce micro-mechanical sensors using micro-machining techniques. In particular, GB 2,276,976 shows a particular method for the production of such a sensor wherein a silicon wafer has cavities formed into its surface. Next a second wafer is bonded to the surface of the first wafer and the second wafer etched in a manner to release portions of the second wafer which are above the cavities in the first wafer. Thus, suspended resonating portions are formed which exist above the cavities in the first wafer.
Further, WO 95/08775 shows a structure wherein a layer of silicon is formed onto a substrate. The silicon is etched in a manner to form suspended resonator portions above cavities in the silicon.
One such micro-mechanical sensor is the vibratory gyroscope which measures the rate of turn and has applications in the fields of vehicle control, smart munitions, robotics, virtual reality, leisure and medicine as well as other fields.